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Date: Sun, 8 Nov 2020 09:33:13 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: alexandru.tachici@...log.com
Cc: linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org,
devicetree@...r.kernel.org, robh+dt@...nel.org
Subject: Re: [PATCH 2/3] hwmon: ltc2992: Add support for GPIOs.
On Thu, Oct 29, 2020 at 11:49:10AM +0200, alexandru.tachici@...log.com wrote:
> From: Alexandru Tachici <alexandru.tachici@...log.com>
>
> LTC2992 has 4 open-drain GPIOS. This patch exports to user
> space the 4 GPIOs using the GPIO driver Linux API.
>
> Signed-off-by: Alexandru Tachici <alexandru.tachici@...log.com>
> Reported-by: kernel test robot <lkp@...el.com>
Please fix the problem reported by 0-day and resubmit.
Thanks,
Guenter
> ---
> drivers/hwmon/Kconfig | 1 +
> drivers/hwmon/ltc2992.c | 160 ++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 161 insertions(+)
>
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index bf9e387270d6..8a8eb42fb1ec 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -861,6 +861,7 @@ config SENSORS_LTC2990
> config SENSORS_LTC2992
> tristate "Linear Technology LTC2992"
> depends on I2C
> + depends on GPIOLIB
> help
> If you say yes here you get support for Linear Technology LTC2992
> I2C System Monitor. The LTC2992 measures current, voltage, and
> diff --git a/drivers/hwmon/ltc2992.c b/drivers/hwmon/ltc2992.c
> index 940d92b4a1d0..3fe6d34cdade 100644
> --- a/drivers/hwmon/ltc2992.c
> +++ b/drivers/hwmon/ltc2992.c
> @@ -9,6 +9,7 @@
> #include <linux/bitops.h>
> #include <linux/bits.h>
> #include <linux/err.h>
> +#include <linux/gpio/driver.h>
> #include <linux/hwmon.h>
> #include <linux/hwmon-sysfs.h>
> #include <linux/i2c.h>
> @@ -56,6 +57,9 @@
> #define LTC2992_G4_MAX_THRESH 0x74
> #define LTC2992_G4_MIN_THRESH 0x76
> #define LTC2992_FAULT3 0x92
> +#define LTC2992_GPIO_STATUS 0x95
> +#define LTC2992_GPIO_IO_CTRL 0x96
> +#define LTC2992_GPIO_CTRL 0x97
>
> #define LTC2992_POWER(x) (LTC2992_POWER1 + ((x) * 0x32))
> #define LTC2992_POWER_MAX(x) (LTC2992_POWER1_MAX + ((x) * 0x32))
> @@ -95,8 +99,18 @@
> #define LTC2992_VADC_UV_LSB 25000
> #define LTC2992_VADC_GPIO_UV_LSB 500
>
> +#define LTC2992_GPIO_NR 4
> +#define LTC2992_GPIO1_BIT 7
> +#define LTC2992_GPIO2_BIT 6
> +#define LTC2992_GPIO3_BIT 0
> +#define LTC2992_GPIO4_BIT 6
> +#define LTC2992_GPIO_BIT(x) (LTC2992_GPIO_NR - (x) - 1)
> +
> struct ltc2992_state {
> struct i2c_client *client;
> + struct gpio_chip gc;
> + struct mutex gpio_mutex; /* lock for gpio access */
> + const char *gpio_names[LTC2992_GPIO_NR];
> struct regmap *regmap;
> u32 r_sense_uohm[2];
> };
> @@ -109,6 +123,8 @@ struct ltc2992_gpio_regs {
> u8 min_thresh;
> u8 alarm;
> u8 alarm_msk;
> + u8 ctrl;
> + u8 ctrl_bit;
> };
>
> static const struct ltc2992_gpio_regs ltc2992_gpio_addr_map[] = {
> @@ -120,6 +136,8 @@ static const struct ltc2992_gpio_regs ltc2992_gpio_addr_map[] = {
> .min_thresh = LTC2992_G1_MIN_THRESH,
> .alarm = LTC2992_FAULT1,
> .alarm_msk = LTC2992_GPIO1_FAULT_MSK,
> + .ctrl = LTC2992_GPIO_IO_CTRL,
> + .ctrl_bit = LTC2992_GPIO1_BIT,
> },
> {
> .data = LTC2992_G2,
> @@ -129,6 +147,8 @@ static const struct ltc2992_gpio_regs ltc2992_gpio_addr_map[] = {
> .min_thresh = LTC2992_G2_MIN_THRESH,
> .alarm = LTC2992_FAULT2,
> .alarm_msk = LTC2992_GPIO2_FAULT_MSK,
> + .ctrl = LTC2992_GPIO_IO_CTRL,
> + .ctrl_bit = LTC2992_GPIO2_BIT,
> },
> {
> .data = LTC2992_G3,
> @@ -138,6 +158,8 @@ static const struct ltc2992_gpio_regs ltc2992_gpio_addr_map[] = {
> .min_thresh = LTC2992_G3_MIN_THRESH,
> .alarm = LTC2992_FAULT3,
> .alarm_msk = LTC2992_GPIO3_FAULT_MSK,
> + .ctrl = LTC2992_GPIO_IO_CTRL,
> + .ctrl_bit = LTC2992_GPIO3_BIT,
> },
> {
> .data = LTC2992_G4,
> @@ -147,9 +169,15 @@ static const struct ltc2992_gpio_regs ltc2992_gpio_addr_map[] = {
> .min_thresh = LTC2992_G4_MIN_THRESH,
> .alarm = LTC2992_FAULT3,
> .alarm_msk = LTC2992_GPIO4_FAULT_MSK,
> + .ctrl = LTC2992_GPIO_CTRL,
> + .ctrl_bit = LTC2992_GPIO4_BIT,
> },
> };
>
> +static const char *ltc2992_gpio_names[LTC2992_GPIO_NR] = {
> + "GPIO1", "GPIO2", "GPIO3", "GPIO4",
> +};
> +
> static int ltc2992_read_reg(struct ltc2992_state *st, u8 addr, const u8 reg_len, u32 *val)
> {
> u8 regvals[4];
> @@ -178,6 +206,134 @@ static int ltc2992_write_reg(struct ltc2992_state *st, u8 addr, const u8 reg_len
> return regmap_bulk_write(st->regmap, addr, regvals, reg_len);
> }
>
> +static int ltc2992_gpio_get(struct gpio_chip *chip, unsigned int offset)
> +{
> + struct ltc2992_state *st = gpiochip_get_data(chip);
> + unsigned long gpio_status;
> + u32 reg;
> + int ret;
> +
> + mutex_lock(&st->gpio_mutex);
> + ret = ltc2992_read_reg(st, LTC2992_GPIO_STATUS, 1, ®);
> + mutex_unlock(&st->gpio_mutex);
> +
> + if (ret < 0)
> + return ret;
> +
> + gpio_status = reg;
> +
> + return !test_bit(LTC2992_GPIO_BIT(offset), &gpio_status);
> +}
> +
> +static int ltc2992_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
> + unsigned long *bits)
> +{
> + struct ltc2992_state *st = gpiochip_get_data(chip);
> + unsigned long gpio_status;
> + unsigned int gpio_nr;
> + u32 reg;
> + int ret;
> +
> + mutex_lock(&st->gpio_mutex);
> + ret = ltc2992_read_reg(st, LTC2992_GPIO_STATUS, 1, ®);
> + mutex_unlock(&st->gpio_mutex);
> +
> + if (ret < 0)
> + return ret;
> +
> + gpio_status = reg;
> +
> + gpio_nr = 0;
> + for_each_set_bit_from(gpio_nr, mask, LTC2992_GPIO_NR) {
> + if (test_bit(LTC2992_GPIO_BIT(gpio_nr), &gpio_status))
> + set_bit(gpio_nr, bits);
> + }
> +
> + return 0;
> +}
> +
> +static void ltc2992_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
> +{
> + struct ltc2992_state *st = gpiochip_get_data(chip);
> + unsigned long gpio_ctrl;
> + u32 reg_val;
> + int ret;
> +
> + mutex_lock(&st->gpio_mutex);
> + ret = ltc2992_read_reg(st, ltc2992_gpio_addr_map[offset].ctrl, 1, ®_val);
> + if (ret < 0) {
> + mutex_unlock(&st->gpio_mutex);
> + return;
> + }
> +
> + gpio_ctrl = reg_val;
> + assign_bit(ltc2992_gpio_addr_map[offset].ctrl_bit, &gpio_ctrl, value);
> +
> + ltc2992_write_reg(st, ltc2992_gpio_addr_map[offset].ctrl, 1, gpio_ctrl);
> + mutex_unlock(&st->gpio_mutex);
> +}
> +
> +void ltc2992_gpio_set_multiple(struct gpio_chip *chip, unsigned long *mask, unsigned long *bits)
> +{
> + struct ltc2992_state *st = gpiochip_get_data(chip);
> + unsigned long gpio_ctrl_io = 0;
> + unsigned long gpio_ctrl = 0;
> + unsigned int gpio_nr;
> +
> + for_each_set_bit(gpio_nr, mask, LTC2992_GPIO_NR) {
> + if (gpio_nr < 3)
> + assign_bit(ltc2992_gpio_addr_map[gpio_nr].ctrl_bit, &gpio_ctrl_io, true);
> +
> + if (gpio_nr == 3)
> + assign_bit(ltc2992_gpio_addr_map[gpio_nr].ctrl_bit, &gpio_ctrl, true);
> + }
> +
> + mutex_lock(&st->gpio_mutex);
> + ltc2992_write_reg(st, LTC2992_GPIO_IO_CTRL, 1, gpio_ctrl_io);
> + ltc2992_write_reg(st, LTC2992_GPIO_CTRL, 1, gpio_ctrl);
> + mutex_unlock(&st->gpio_mutex);
> +}
> +
> +static int ltc2992_config_gpio(struct ltc2992_state *st)
> +{
> + const char *name = dev_name(&st->client->dev);
> + char *gpio_name;
> + int ret;
> + int i;
> +
> + ret = ltc2992_write_reg(st, LTC2992_GPIO_IO_CTRL, 1, 0);
> + if (ret < 0)
> + return ret;
> +
> + mutex_init(&st->gpio_mutex);
> +
> + for (i = 0; i < ARRAY_SIZE(st->gpio_names); i++) {
> + gpio_name = devm_kasprintf(&st->client->dev, GFP_KERNEL, "ltc2992-%x-%s",
> + st->client->addr, ltc2992_gpio_names[i]);
> + if (!gpio_name)
> + return -ENOMEM;
> +
> + st->gpio_names[i] = gpio_name;
> + }
> +
> + st->gc.label = name;
> + st->gc.parent = &st->client->dev;
> + st->gc.owner = THIS_MODULE;
> + st->gc.base = -1;
> + st->gc.names = st->gpio_names;
> + st->gc.ngpio = ARRAY_SIZE(st->gpio_names);
> + st->gc.get = ltc2992_gpio_get;
> + st->gc.get_multiple = ltc2992_gpio_get_multiple;
> + st->gc.set = ltc2992_gpio_set;
> + st->gc.set_multiple = ltc2992_gpio_set_multiple;
> +
> + ret = devm_gpiochip_add_data(&st->client->dev, &st->gc, st);
> + if (ret)
> + dev_err(&st->client->dev, "GPIO registering failed (%d)\n", ret);
> +
> + return ret;
> +}
> +
> static umode_t ltc2992_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
> int channel)
> {
> @@ -701,6 +857,10 @@ static int ltc2992_i2c_probe(struct i2c_client *client, const struct i2c_device_
> if (ret < 0)
> return ret;
>
> + ret = ltc2992_config_gpio(st);
> + if (ret < 0)
> + return ret;
> +
> hwmon_dev = devm_hwmon_device_register_with_info(&client->dev, client->name, st,
> <c2992_chip_info, NULL);
>
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